If you need to do the box, I would just do the box. One of the challenges of rewires was with older knob and tube wirings, there was a common practice of splices all over the place, and so it was hard to map out wiring runs for a rewire. ALuminum wiring is at least done just like copper wiring. While others have mentioned , like joining galvanized and copper pipes, special precautions need to be taken when mixing metals, I don't think there's a big advantage to having an electrician do the box and rewire versus an electrician doing the box, and then the rewire down the road if you proceed that way. A new box is still a reasonable chunk of a job that amortizes some of the costs of bidding, site visit, overhead etc that you might save on by combining into a larger project.
Also, if an older house, you may likely be tearing into walls later, which would make the rewire much easier. Lastly, we found in renovations you often want to cange te placement or number of fixtures and receptacles. So if the panel is the issue, and if you haven't considered do bring the panel up to 200 amps to futureproof your house, and leave the rewire til a later date.